Device and method for producing a load bearing cable, as well as a load bearing cable

ABSTRACT

A device 100 produces an endless winding cable 101 by winding a yarn 106 around two thimbles 102, 104. The device 100 comprises an elongated guide 110, a carriage 112, a yarn feeder 114, a first thimble holder 116, and a second thimble holder 118. The first thimble holder 116 and the second thimble holder 118 each hold one of the two thimbles 102, 104. The carriage 112 is movable relative to the elongated guide 110. The yarn feeder 114 is connected to the carriage 112, and comprises at least one spool holder 120 for holding a spool 122 with the at least one yarn 106, and an output guide 124 for guiding the at least one yarn 106 to the cable during winding. The yarn feeder 114 comprises at least one yarn brake 126 for controlling a tension of the at least one yarn 106 during winding.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application (under 35 USC § 371) ofPCT/NL2016/050849, filed Dec. 6, 2016, which claims benefit ofNetherlands application No. 2015920, filed Dec. 7, 2015, the contents ofeach of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

A cable produced by a device or method for producing an endless windingcable can be used in different types of industry, including but notlimited to offshore, mining and heavy lifting and construction. Inoffshore, such a cable may be used as a mooring line for ships andstructures like a floating oil exploration or production facility, or afloating wind turbine. In mining and heavy lifting such a cable may beused as a pendant for a crane. In construction these cables may be usedas a tension member in a bridge or a roof.

A cable produced by a device of this type is known fromWO-A1-2005/075286, which discloses a cable that is used as a stay forsailing vessels. This document discloses that fibres/fibers of athermoplastic material are wound around two fastening eyes with theirlongitudinal direction running parallel to the longitudinal direction ofthe stay. The wound fibres/fibers form an endless loop, as it were,comprising a first fibre/fiber strand and a second fibre/fiber strand.As it is an endless loop, the first strand and second strand are in factone and the same, but in a cross section there appear to be two strands,forming a plastic cable. Due to the thermoplastic material used andbecause the fastening elements have been incorporated in the loop ofplastic fibres/fibers, a stay of this type has good strength properties.

A device and method for producing an endless winding cable is known froma video, published by FibreMax on YouTube on 27 Jan. 2015. The videoshows a device elongated guide, a carriage, a yarn feeder, a firstthimble holder, and a second thimble holder. The thimble holders areconnected to the elongated guide at a distance from one another. Thecarriage is movable along the elongated guide. The yarn feeder isconnected to the carriage, and comprises several spool holders forholding a spool, and an output guide for guiding the yarns to the cableduring winding. The output guide is movable relative to the first andsecond thimble holders for guiding the yarns half a turn around thefirst thimbles during winding.

The concept of endless winding cable, or rope, is also explained on thepage Rope of the English version of Wikipedia as follows. ‘Endlesswinding rope is made by winding single strands of high-performance yarnsaround two end terminations until the desired break strength orstiffness has been reached. This type of rope (often specified as cableto make the difference between a braided or twined construction) has theadvantage of having no construction stretch as is the case with aboveconstructions. Endless winding is pioneered by SmartRigging andFibreMax.’

The known devices and methods for producing an endless winding cablehave as a disadvantage that the maximum load of the resulting cable islower than the sum of the strengths of the individual turns of the yarn.

The invention aims to solve to this problem, or at least to provide analternative. In particular, the invention aims to provide a device and amethod which has an increased break load for the same number of yarnturns.

SUMMARY OF THE INVENTION

A device for producing an endless winding cable by winding at least oneyarn around two thimbles that are provided at opposite ends of the cablecomprises an elongated guide, a carriage, a yarn feeder, a first thimbleholder, and a second thimble holder. The first thimble holder and thesecond thimble holder are connected to the elongated guide at a distancefrom each other, and are each designed to hold one of the two thimbles.The elongated guide and the carriage are movably connected to oneanother to allow a movement of the carriage relative to the elongatedguide in a length direction of the elongated guide. The yarn feeder isconnected to the carriage, and comprises at least one spool holder forholding a spool with the at least one yarn, and an output guide forguiding the at least one yarn to the cable during winding. The outputguide and the first thimble holder, as well as the output guide and thesecond thimble holder, are movable relative to each other in at least adirection perpendicular to the length direction of the elongated guidefor guiding the at least one yarn half a turn around respectively thefirst thimble and the second thimble during winding. The yarn feedercomprises at least one yarn brake for controlling a tension of the atleast one yarn during winding.

The yarn brake for controlling a tension of the at least one yarn duringwinding results in a cable wherein turns of the at least one yarn have apredetermined amount of tension. This prevents individual yarn turnsfrom becoming overloaded, while other yarn turns are still well underthe maximum load, when the cable as a whole is subjected to a load. Thisinvention is based on the insight that in prior art cables individualyarn turns could have more pre stress than others, resulting in suchyarn turns becoming individually overloaded and breaking prematurely.This resulted in a lower than expected maximum load of the cable as awhole, as fewer yarn turns contributed to the maximum load of the cablethan designed. According to the invention, more yarns remain intact whenthe cable is subjected to a load, and accordingly the maximum load ofthe resulting cable is greater.

The device comprises a control, wherein the at least one yarn brake iscontrollable by the control to adjust, in particular increase, thetension during winding. Adjusting the tension during winding results ina cable wherein yarn turns have a mutually differing predeterminedamount of pre tension. This difference may take into account specificproperties of the yarns. In particular, some types of fibres/fibersmaking up yarns have a decreased maximum load when they are compressed.Such compression occurs at the thimbles, where inward layers of yarnturns are compressed by outward layers of yarns that have to transfertheir load to the respective thimble via the inward layers of turns.Accordingly, these inward layers will fail prematurely. By controllingthe tension, such inward layers can be given a lower pre-tension thanoutward layers, so that the total tension of the yarn turns in theinward layers is lower than the total tension of the yarn turns in theoutward layers when the cable is subjected to a load. This reduces therisk of premature failing of yarn turns in the inward layers due to thecombination of tension and compression.

In particular, the control comprises a tension meter for measuring atension of the at least one yarn at the output guide. A tension meterincreases the accuracy of the tension control.

In an embodiment, the control comprises a spool meter for measuring anouter diameter of the at least one spool. This improves the control ofthe yarn tension.

In an embodiment, the at least one yarn brake is a friction brake, inparticular an electro-mechanical brake. Such a brake is wellcontrollable.

In an embodiment, the at least one yarn brake is an eddy current brake.Such a brake does not wear and accordingly the break force does notchange over the lifetime of the brake.

In an embodiment, at least one of the first thimble holder and thesecond thimble holder is detachably connected to the elongated guide,and is connectable to the elongated guide at a plurality of differentpositions along the elongated guide for adjusting the distance betweenthe two thimbles. This enables producing cables of different lengthswith the same device.

In an embodiment, the first thimble holder comprises a main frame and asub-frame, wherein the main frame is connected to the elongated guide,the sub-frame is designed to hold one of the two thimbles, and the mainframe and sub-frame are movably connected to each other for adjustingthe distance between the two thimbles. This enables producing cables ofdifferent lengths with the same device. It also enables varying thetension in subsequent layers of yarn turns. In particular, at least oneof the first thimble holder and the second thimble holder is detachablyconnected to the elongated guide and the first thimble holder comprisesa main frame and a sub-frame. In such an embodiment the detachableconnection is intended for a rough determination of the cable length,while the main frame and sub-frame are for fine tuning the cable length.

In particular, the first thimble holder comprises an actuator for movingthe main frame and the sub frame with respect to each other. Thisenables an automated adjustment of the first thimble holder.

In an embodiment, the yarn feeder comprises a plurality of spoolholders, each for holding a spool with a yarn. This increases theproduction speed of the device as compared to a device having one spoolholder.

A method for producing an endless winding cable according to theinvention comprises the steps of:

positioning a first thimble and a second thimble at a predetermineddistance from one another, which distance corresponds to a requiredcable length,

providing at least one yarn,

winding the at least one yarn from the first thimble to the secondthimble, a half turn around the second thimble, back to the firstthimble, and a half turn around the first thimble,

repeating the previous step until a predetermined number of layers ofyarn turns is provided in both the first thimble and the second thimble,corresponding to a required cable thickness, wherein

a tension of the at least one yarn is controlled during winding.

Controlling a tension of the at least one yarn during winding results ina cable wherein turns of the at least one yarn have a predeterminedamount of tension. This solves the problem of the prior art in a similarmanner as described above in relation to the device.

In an embodiment, the tension of the at least one yarn is greater whilewinding a subsequent layer of yarn turns than is the tension of the atleast one yarn in at least one of the previous layers of yarn turns.Providing a higher tension in a subsequent layer than in a previouslayer results in a cable wherein the yarn turns in the subsequent layerhave more pre-tension than the yarn turns in the previous layer.Accordingly, when the cable receives a load, the tension in the previouslayer is lower. This enables the use of fibres/fibers of which themaximum load decreases when being compressed.

In an embodiment, the tension of the at least one yarn is at leastequal, and preferably greater, while winding each subsequent layer ofyarn turns, than the tension of the at least one yarn in each previouslayer of yarn turns. This embodiment provides a compensation for reducedload under compression of the previous embodiment to all layers of thecable.

In an embodiment, the tension of the at least one yarn is greater whilewinding a final layer of yarn turns, than the tension of the at leastone yarn while winding a first layer of yarn turns.

In an embodiment, the tension of the at least one yarn is controlledduring winding by controlling a brake force that is exerted on the atleast one yarn during winding. Using a break force is an effectivemanner of controlling the tension.

In an embodiment, the predetermined distance between the first thimbleand the second thimble is decreased after winding a previous layer ofyarn turns and the relevant half turn around the first thimble. This isan alternative way of reducing pre tension in a previous layer of yarnturns relative to a subsequent layer of yarn turns.

In an embodiment, the winding of the at least one yarn from the firstthimble to the second thimble, a half turn around the second thimble,back to the first thimble, and a half turn around the first thimble, isrepeated until one layer of a predetermined plurality of yarn turns isprovided in both the first thimble and the second thimble. In thismanner, a cable is produced with more yarn turns in one layer than thenumber of yarns that is used for winding. This results in strongercable.

Preferably the tension of the at least one yarn is kept constant whilewinding the one layer of yarn turns. This ensures that all yarn turns inone layer get the same pre tension and thus the same load when the cableis under load.

In an embodiment, the at least one yarn is a plurality of yarns.Accordingly, the method comprises the step of winding the plurality ofyarns from the first thimble to the second thimble, a half turn aroundthe second thimble, back to the first thimble, and a half turn aroundthe first thimble. The effect of this feature is that a plurality ofyarn turns is provided in the first and second thimble in one methodstep, which decreases the required time for producing a cable.

In practice, most cables require layers which have each a plurality ofyarn turns. This plurality can be produced by either one of, or acombination of, the previous two preferred embodiments, i.e. repeatingwinding yarn turns for one layer and/or winding more yarn turns in onego.

A cable produced by endless winding of at least one yarn around twothimbles comprises a first thimble and a second thimble, and at leastone yarn. The first thimble and the second thimble are provided atopposite ends of the cable. The at least one yarn extends from the firstthimble to the second thimble, turns around the second thimble, extendsfrom the second thimble to the first thimble, and turns around the firstthimble, such that the at least one yarn forms a turn around the firstthimble and the second thimble, and each thimble holds a stack of aplurality of layers of turns of the at least one yarn. Within thecontext of this document, a turn of a yarn may be either asemi-continuous loop, or a continuous loop. The term semi-continuousloop refers to the fact that the yarn has a finite length with distinctends, while in a continuous loop a yarn has no ends. So in asemi-continuous loop, the at least one yarn is wound around the firstand second thimble a plurality of times, forming a plurality of loopsaround these thimbles, which is not completely continuous as the ends ofthe yarn are not connected to each other. A previous layer of turns ofthe at least one yarn and a subsequent layer of turns of the at leastone yarn are defined with respect to a centre/center of the respectivethimble, in that the subsequent layer of turns of the at least one yarnis farther away from the centre/center of the respective thimble, thanthe previous layer of turns of the at least one yarn. Previous andsubsequent are relative terms. Accordingly, all layers, except for anoutermost layer, will be previous layer with respect to one or morelayers that are farther away from the centre/center of the respectivethimble. At the same time, all layers except for an innermost layer,will be a subsequent layer with respect to one or more layers that arecloser to the centre/center of the respective thimble. A yarn tension isdefined as the tension in the at least one yarn in a specific turn. Ayarn tension in the subsequent layer of turns of the at least one yarnis greater than the yarn tension in the previous layer of turns of theat least one yarn.

Having a yarn tension in the subsequent layer of turns of the at leastone yarn that is greater than the yarn tension in the previous layer ofturns of the at least one yarn reduces the risk of premature failing dueto compression of the yarn turns in the previous layer, as has beenexplained in detail in relation to the inventive method and device. Theyarn tension is determined either while the cable is not under a load,or while it is under a load, in particular under a relative small loadjust to stretch the cable.

In an embodiment, the stack of a plurality of layers of turns of the atleast one yarn is a stack with at least three layers of turns of the atleast one yarn, and the yarn tension in every subsequent layer is atleast equal to, preferably higher than, the yarn tension in each of theprevious layers. This embodiment provides the compensation for reducedload under compression of the previous embodiment to all layers of thecable.

In an embodiment, the at least one yarn comprises fibres/fibers, inparticular carbon fibres/fibers, basalt fibres/fibers, or plasticfibres/fibers, in particular thermoplastic fibres/fibers, more inparticular polyamide fibres/fibers, polyester fibres/fibers,polypropylene fibres/fibers, polyethylene fibres/fibers, aramidfibres/fibers, HMPE fibres/fibers, LCAP fibres/fibers, or PBOfibres/fibers. Each of these types of fibres/fibers has its ownproperties, which makes them suitable for specific uses of the cable.

In an embodiment, the cable comprises a cable cover, which extendsaround the cable from the first thimble to the second thimble, andbundles all turns of the at least one yarn extending between the firstand the second thimble in one compact bundle in a middle section of thecable. This results in a compact cable.

DESCRIPTION OF THE DRAWINGS

The invention, its effects, and advantages will be explained in moredetail on the basis of the drawing, in which

FIG. 1 shows an end of a cable according to the invention;

FIG. 2 shows section II-II from FIG. 4;

FIG. 3 shows a detail from FIG. 2;

FIG. 4 shows a top view of the cable of FIG. 1;

FIG. 5 shows section V-V from FIG. 4;

FIG. 6 shows a perspective view of a device according to the invention;

FIG. 7 shows a top view of the device of FIG. 6;

FIG. 8 shows a side view of the device of FIG. 6;

FIG. 9 shows an end view of the device of FIG. 6;

FIG. 10 shows an end view of the device of FIG. 6, seen from an endopposite to FIG. 9;

FIG. 11 shows the device of FIG. 6 in use;

FIG. 12 shows an end view of the device of FIG. 6 in use;

FIG. 13 shows section XIII-XIII from FIG. 11;

FIG. 14 shows control components of the device of FIG. 6; and

FIG. 15 shows a control circuit for controlling the device of FIG. 6.

DETAILED DESCRIPTION

The FIGS. 1-5 show a cable according to the invention, which is denotedin its entirety by reference number 1. The cable 1 has a first thimble 2and a second thimble 4, and a plurality of yarns 6. The first 2 and thesecond 4 thimble are made of stainless steel, and are provided atopposite ends of the cable 1. The plurality of yarns 6 are in thisembodiment ten yarns 6 which all extend from the first to the secondthimble, turn around the second thimble 4, extend from the secondthimble 4 to the first thimble 2, and turn around the first thimble 2.In this manner each of the plurality of yarns 6 forms a semi-continuousloop around the first and second thimbles. This loop is repeated aplurality of times, in this embodiment 950 times. So each of the yarns 6makes 950 turns, resulting in a total of 9500 turns of yarns 6. Thiswill be explained in more detail later when describing the device andmethod according to the invention. The yarns 6 consist of fibres/fibers,in this embodiment aramid fibres/fibers with a density of 3220 dTex thatare provided with a marine coating. This coating makes the fibres/fiberssmoother which results in less fibre-to-fibre wear. These yarns are soldunder the name Twaron® D2204 by Teijin Aramid.

FIG. 2 shows that the thimble 2 holds a stack 9 with a plurality oflayers 10 of yarn turns 6. This is shown in more detail in FIG. 3. Inthe upper part of FIG. 2 the stack 9 is shown in an exploded view forclarity. In reality, the stack 9 is held in the first thimble 2 as shownin the lower part of FIG. 2. The second thimble 4 holds layers of thesame yarn turns 6 in the same manner and is therefore not shown indetail.

An inside 12 of the stack 9 is defined as a side of a first layer 13 ofyarn turns 6 being closest to a centre/center 14 of the thimble 2. Anoutside 16 of the stack 9 is defined as a side of a last layer 15 ofyarn turns 6 being farthest away from the centre/center 14 of thethimble 2. A stack height h is defined as the distance from the insideof the stack 12 to the outside of the stack 16. A previous layer 18 ofturns of the at least one yarn 6 and a subsequent layer 20 of turns ofthe at least one yarn 6 are defined with respect to the centre/center 14of the first thimble 2, in that the subsequent layer 20 of turns of theat least one yarn 6 is further away from the centre/center 14 of therespective thimble 2, than the previous layer 18 of turns of the atleast one yarn 6.

A cable cover 28 extends around the cable 1 from the first thimble 2 tothe second thimble 4, and bundles all yarn turns 6 extending between thefirst and the second thimble 2, 4 in one compact bundle 30 in a middlesection 32 of the cable 1. In this embodiment, the cable cover 28 alsocovers the yarn turns 6 at the thimbles 2, 4.

The turns of the yarn 6 have a specific predetermined tension, whichwill be explained in more detail in below examples.

A device 100 according to the invention is shown in FIGS. 6-15. Thedevice 100 is designed to produce an endless winding cable 101 bywinding at least one yarn 106, in this embodiment ten yarns 106simultaneously, around two thimbles 102, 104 that are provided atopposite ends of the cable 101. The device 100 comprises an elongatedguide 110, a carriage 112, a yarn feeder 114, a first thimble holder116, and a second thimble holder 118. In this embodiment the elongatedguide 110 comprises two elongated I-profiles 119. The elongated guide110 is suspended from a ceiling of a production facility via supports(not shown) at an interval of approximately 2 meters.

The yarn feeder 114 comprises in this embodiment ten spool holders 120,each designed for holding a spool 122. Each of the ten spools 122 holdsa yarn 106. The yarn feeder 114 further comprises an output guide 124for guiding all ten yarns 106 to the cable 101 during winding (see FIG.11-13). The output guide 124 of this embodiment comprises rollers forguiding the ten yarns 106, and is in a fixed position relative to theyarn feeder 114. This fixed position is offset from a middle of the yarnfeeder 114.

The yarn feeder 114 is connected to the carriage 112, in this embodimentvia a pivot 125, which pivot is positioned at the middle of the yarnfeeder 114. This enables the yarn feeder 114 to rotate about a verticalaxis with respect to the carriage 112. This rotation results in theoutput guide 124 moving along an arc, in this case a semi-circle, withrespect to the elongated guide 110 and thus relative to the firstthimble holder 116 and to the second thimble holder 118. Thissemi-circle includes a movement in a direction perpendicular to thelength direction of the elongated guide 110, and enables the outputguide 124 to guide the ten yarns 106 half a turn around respectively thefirst thimble 102 at the first thimble holder 116 and the second thimble104 at the second thimble holder 118 during winding when the outputguide 124 is just beyond the respective one of the two thimbles 102,104.

The yarn feeder 114 further comprises ten yarn brakes 126, each for oneof the spools 122, for controlling a tension of the respective yarn 106during winding. In this embodiment, the yarn brakes 126 areelectro-mechanical brakes. The working and control of the yarn brakes126 will be explained in more detail in relation to FIGS. 14 and 15.

The first thimble holder 116 and the second thimble holder 118 areconnected to the elongated guide 110 at a distance from each other, andare each designed to hold one of the two thimbles 102, 104. In thisembodiment, the first thimble holder 116 comprises a main frame 128 anda sub-frame 130, wherein the main frame 128 is connected to theelongated guide 110, the sub-frame 130 is designed to hold one thimble102, and the main frame 128 and sub-frame 130 are movably connected toeach other for adjusting the distance between the two thimbles 102, 104.An actuator 132 is operably connected to the main frame 128 and thesub-frame 130 for moving the main frame 128 and the sub frame 130 withrespect to each other. The actuator 132 comprises a spindle motor 133, agearbox 134, a spindle 135, and a spindle nut (not shown). The spindlemotor 133, and gearbox 134 are mounted on the main frame 128. Thespindle nut is connected to the sub-frame 130. Rotation of the spindlemotor 133 results in a linear movement of the spindle nut and thus thesub-frame 130 relative to the main frame 128.

In this embodiment, both the first thimble holder 116 and the secondthimble holder 118 are each detachably connected to the elongated guide110 via a fastener. This fastener comprises in this embodiment a pin anda hole. The elongated guide 110 comprises the respective holes 136. Theholes 136 have a mutual distance of 15 cm. The pins (not shown in thefigures) are movably held in the respective thimble holder 116, 118 forconnecting the respective thimble holder 116, 118 to the elongated guide110 at a plurality of different positions along the elongated guide 110,which positions are defined by the holes 136. By retracting the pin, therespective thimble holder 116, 118 is disconnected from the elongatedguide 110 and can be moved along the elongated guide 110 for adjustingthe distance between the two thimbles 102, 104. The pins are enteredinto one of the holes 136 when the respective thimble holder 116, 118 isat a required position. This enables producing cables 101 of differentlengths with the same device.

The carriage 112 is connected with the elongated guide 110 for amovement of the carriage 112 along the elongated guide 110 in a lengthdirection of the elongated guide 110. The movable connection comprisesin this embodiment wheels 140 that run inside the two elongatedI-profiles 119 of the elongated guide 110. The carriage 112 furthercomprises a carriage motor 148 for moving the carriage along theelongated guide 110. The carriage motor 148 is shown only schematicallyin FIG. 15.

This embodiment of the inventive device comprises a control 150, whichcomprises an electronic control unit 151. The electronic control unit151 is operatively connected to the yarn brakes 126 in order to adjust,in particular increase, the tension during winding. The control 150further comprises ten tension meters 152, and ten spool meters 154, oneof each being associated with one of the spools 122 (see also FIG. 14).The control 150 further comprises a user interface 156, and isoperatively connected to the carriage motor 148, the spindle motor 133,and a pivot motor 158. The pivot motor 158 is shown only schematicallyin FIG. 15, and is operatively connected to the carriage 112 and theyarn feeder 114 in order to rotate yarn feeder 114 about pivot 125 withrespect to the carriage 112. The connections between the components ofthe control 150 may be wired, or wireless.

The tension meter 152 of this embodiment comprises three guide wheels160, 162, 164, see FIG. 14. The axles of two outer wheels 160, 164 aremounted at a fixed position on the yarn feeder 114 (not shown in FIG.14), while the axle of the middle wheel 162 is movably mounted on a rod166, which rod is mounted at a fixed position on the yarn feeder 114.The rod 166 is positioned offset with respect to the two outer wheels160, 164, and is oriented on a line that runs between the two outerwheels 160, 164. A helical spring 168 is mounted around the rod 166, andholds the middle wheel 162 under spring force. The respective yarn 106runs from the spool 122 via the wheels 164, 162, 160 to the output guide124. Due to the offset position of the middle wheel 162 with respect tothe two outer wheels 160, 164, the yarn 106 forms a U-shaped line,running from the first of the two outer wheels 164, via the middle wheel162, to the second of the two outer wheels 160. The tension meter 152further comprises a position meter 170 which is connected to the middleguide wheel 162 and provides position information to the electroniccontrol unit 151. This position information corresponds to the actualtension in the respective yarn 106, thanks to the spring action of thehelical spring 168.

The spool meter 154 for each spool 122 is in this embodiment a laserwith an associated photosensor. The spool meter 154 measures an outerdiameter of the associated spool 122. This information is provided tothe control unit 151. The control unit 151 controls the yarn brakes 126in order to determine the required yarn tension during the winding of aspecific layer of yarn turns. This yarn tension and its preferredvariation will be discussed in relation to the below examples. Here itsuffices to say that this yarn tension is computed by the control unit151 depending on the characteristics of the cable that will be producedand that are input via the user interface 156. The yarn brake 126 is anelectromagnetic brake which is controlled precisely by varying theelectrical resistance over the electric spool (not shown) of the yarnbrake 126. This arrangement results in a torque, which is applied on thespool holder 120 and thus the spool 122. This torque results in acertain tension on the yarn 106. The amount of the tension depends onthe actual diameter of the spool 122. Because of this relationship, thediameter is continuously and precisely measured by spool meter 154. Putdifferently, the required yarn tension and the actual measure spooldiameter result in feed forward information on the required yarn braketorque.

The tension meter 152 provides a feedback loop to control unit 151 bymeasuring the actual yarn tension. On the basis of this feedbackinformation, the control unit 151 can adjust the yarn break torque ofthe yarn brake 126.

A method for producing an endless winding cable preferably uses adevice, such as device 100 which has been described above. For the sakeof clarity, the method will be described below in relation to thisdevice. It should be noted however, that any other device or tools maybe used within the scope of the invention, as longs as it operatesaccording to a method within the scope of the attached method claims.

The method starts with positioning a first thimble 102 and a secondthimble 104 at a predetermined distance from one another, which distancecorresponds to a required cable length. Ten yarns 106 are provided onthe spools 122, which are held on the spool holder 120 of the yarnfeeder 114 as described above. The carriage 112 moves along theelongated guide 110. At the same time, the ten yarns 106 are wound offfrom the spools 122 while having a precise controlled yarn tension,using yarn brakes 126 under control of control 150. This control 150also controls the carriage motor 148 and thus the speed of the carriage112. The carriage 112 moves from the first thimble holder 116 to thesecond thimble holder 118, thus winding the ten yarns 106 from the firstthimble 102 to the second thimble 104. When the carriage arrives at thesecond thimble holder 118, the control unit 150 controls the pivot motor158 such that the spool holder 114 makes a half turn. This results inthe spool guide 124 making a half turn around the second thimble 104,such that the ten yarns 106 make a first half turn around the secondthimble 104. Then the carriage 112 moves back to the first thimbleholder 116 so that the ten yarns 106 run back to the first thimble 102,where the control unit 150 again controls the pivot motor 158 such thatthe spool holder 114 and thus the spool guide 124 make another half turnsuch, that the spool guide 124 lets the ten yarns 106 make a second halfturn around the first thimble 102. These movements of the carriage 112and spool holder 114 are repeated using the same yarn tension,controlled by control 150, in case that the first and second thimbles102, 104 are so wide that a multitude of ten yarn turns are providednext to each other in one layer. If only ten yarn turns are providednext to each other in one layer, then the device immediately proceeds tomaking a next layer.

Once a first layer of yarn turns is provided in both the first thimbleand the second thimble 102, 104, preferably the yarn tension isincreased as will be explained below in relation to the examples. Thenthe movements of the carriage 112 and spool holder 114 are repeateduntil the next layer of yarn turns is provided in the first and secondthimble 102, 104. The increasing of the yarn tension, followed by movingthe carriage 112 and spool holder 114, is repeated until a predeterminednumber of layers of yarn turns is provided in both the first thimble 102and the second thimble 104. This predetermined number of layers of yarnturns corresponds to a required cable thickness.

In order to finish the cable 101, a cable cover is provided around theturns of the yarn 106, such as the cable cover 28 which is shown inFIGS. 2 and 5. Such a cable cover bundles the turns of the yarn 106 intoone compact bundle. Preferably, the same or another cover also coversthe yarns which loop around the thimbles 102, 104.

A first example is a cable made of yarns of aramid fibres/fibers with adensity of 3220 dTex that are provided with a marine coating. Theseyarns are sold under the name Twaron® D2204 by Teijin Aramid. The lengthof the cable is 25 meters. The cable is made of a total of 9500 yarnturns, by winding 10 yarns at a time. There are 30 yarn turns in onelayer, and 317 layers. The yarn tension while winding the first layer is0.5 N. The yarn tension is increased by 0.1 N before winding every nextlayer. Accordingly the final layer is wound with a tension of about 32.2N in each yarn.

A second example is a cable made of Twaron® D2204 yarns as well. Thelength of the cable is 29 meters. The cable is made of a total of 3490yarn turns, by winding 10 yarns at a time. There are 20 yarn turns inone layer, and 175 layers. The yarn tension while winding the firstlayer is 0.5 N. The yarn tension is increased by 0.2 N before windingevery next layer. Accordingly the last layer is wound with a tension of35 N in each yarn.

A third example is a cable made of Twaron® D2204 yarns as well. Thelength of the cable is 45 meters. The cable is made of a total of 8800yarn turns, by winding 10 yarns at a time. There are 30 yarn turns inone layer, and 293 layers. The yarn tension while winding the firstlayer is 0.5 N. The yarn tension is increased by 0.15 N before windingevery next layer. Accordingly the last layer is wound with a tension of44 N in each yarn.

A fourth example is a cable made of Dyneema® DM 20 yarns of 1760 dtex.Dyneema® is a trade mark of DSM, the Netherlands. Dyneema fibres/fibersare made of Ultra-High Molecular Weight Polyethylene (UHMwPE), alsoknown as high-modulus polyethylene (HMPE). The length of the cable is 29meters. The cable is made of a total of 47870 yarn turns, by winding 10yarns at a time. There are 100 yarn turns in one layer, and 479 layers.The yarn tension while winding the first layer is 0.5 N. The yarntension is increased by 0.1 N before winding every next layer.Accordingly the last layer is wound with a tension of 48 N in each yarn.

A fifth example is a cable made of yarns of carbon fibres/fibers, inthis case called filaments, made by Toho Tenax Europe GmbH. The productname is Tenax® UTS50 F24 24K 1600 tex D. This yarn has 24000 filaments,which corresponds to a nominal linear density of 1600 tex. Tenax® is atrade mark of Toho Tenax. The length of the cable is 12.5 meters. Thecable is made of a total of 470 yarn turns, by winding 10 yarns at atime. There are 40 yarn turns in one layer, and 12 layers. The yarntension while winding the first layer is 0.5 N. The yarn tension isincreased by 15 N before winding every next layer. Accordingly the lastlayer is wound with a tension of 162 N in each yarn. It should be notedthat the tension increase for each layer is far greater than for used inwinding the thermoplastic fibres/fibers of the previous examples,reflecting the unique tensile properties of carbon fibres/fibers.

Variants of the shown embodiments of the device, method, and cable arewell possible within the scope of the attached claims. It is possible tocombine one or more features of one embodiment with one or more featuresof another embodiment. The features of the above described embodimentsmay be replaced by any other feature within the scope of the attachedclaims, such as the features described in the following paragraphs.

A cable according to the invention may be made of more or less than tenyarns, such as one yarn, two yarns, or at least five yarns. The totalnumber of yarn turns, i.e. yarn turns per layer and number of layers,depends on the required strength of the cable, and the strength of oneindividual yarn, as well as the required safety margin. The number ofyarn layers in the stack of layers is at least one, but is usually aplurality of layers. The number of layers depends on the required numberof yarn turns, and the available width in the thimble resulting in amaximum number of yarn turns in the width direction.

Different types of yarns may be used, such as aramid yarns with adensity of 1610 dTex, 6440 dTex, or 4830 dTex, with or without acoating. Instead of using aramid fibres/fibers, one could use othertypes of plastic fibres/fibers, in particular thermoplasticfibres/fibers, such as polyamide fibres/fibers, polyester fibres/fibers,polypropylene fibres/fibers, polyethylene fibres/fibers, HMPEfibres/fibers, LCAP fibres/fibers, or PBO fibres/fibers. The cable couldeven comprise other types of yarns, e.g. yarns made of carbonfibres/fibers, a metal, or a natural fibre/fiber, such as basaltfibres/fibers. Yarns of fibres/fibers may consist for 100% of therelevant fibre/fiber type, but could also comprise a small portion of anauxiliary material, e.g. a coating on the fibres/fibers to protect thefibres/fibers against wear and/or environmental influences. As suchauxiliary material is only a small portion in weight, and does notcontribute to the strength of the cable, the phrase ‘yarn consisting offibres’ or ‘yarn consisting of fibers’ is considered to includeembodiments with such auxiliary materials within the context of thisdocument.

The thimble may be made of a plastic material instead of a metal, or ofa different metal than stainless steel, including but not limited todifferent steel alloys, aluminium alloys, magnesium alloys, andtitanium.

A device according to the invention has some of the components connectedfixedly to each other, instead of connecting the different components ofthe device detachably and movably to each other as in the shownembodiment. By connecting fixedly one or both thimble holders to theelongated guide, a more simple construction is possible. If one thimbleholder is connected fixedly, and the other detachably at differentpositions, it is still possible to produce cables of different lengths.If both thimble holders are connected fixedly, cables of one length canbe produced, or if such an embodiment has a thimble holder with a mainframe and sub-frame the cable length can still be varied insofar themovability of the sub-frame relative to the main frame allows. It isfurther possible to connect the components in an indirect manner to eachother, e.g. via the ground or another construction such as a wall orceiling of a building. As an example, the thimble holders may beconnected directly to a ceiling of a building, instead of via theelongated guide.

In an alternative embodiment, the carriage and the yarn feeder areconnected to a fixed construction, while the elongated guide and boththimble holders are connected to each other and jointly movable withrespect to the carriage and thus with respect to the yarn feeder too.

In a simple embodiment, the spool holder and the output guide may beintegrated. The movement of the output guide relative to the first andsecond thimble holder may be implemented in alternative ways. The outputguide may be movable with respect to the yarn feeder, in particularalong a line at least partly perpendicular to the length direction ofthe elongated guide, instead of moving the whole yarn feeder relative tothe carriage. In a further alternative embodiment, the first and secondthimble holder are movable with respect to the elongated guide, and thusthe output guide, perpendicular to the length direction of the elongatedguide.

In alternative embodiments of both the method and the device, thepredetermined distance between the first thimble and the second thimbleis decreased after winding a previous layer of yarns and before windinga subsequent layer of yarn turns. This results in a cable wherein thepre-tension of the yarn turns in each subsequent layer is more than thepre-tension of the yarn turns in each previous layer. The decrease perlayer for the cables of the above examples would be in the range of 0.1to 1 mm. In general, the decrease depends on the length and thickness ofthe cable and modulus of elasticity of the yarns. Longer cables thanshown as examples require a larger decrease. Stiffer cables require lessdecrease.

Instead of a central control unit, a control device may comprise atleast one separate component for controlling the movement of thecarriage, the yarn break, and/or the actuator of the first thimbleholder.

In an embodiment, the elongated guide comprises one member, or more thantwo members. In an alternative embodiment, the elongated guide comprisesT-shaped members. In an embodiment, the elongated guide comprises a rackwhich cooperates with a pinion for driving the carriage. In anembodiment, the movable connection between the carriage and theelongated guide comprises a linear slide.

The yarn brake may either engage on the spool, or directly on the yarn.In an embodiment, the yarn brake is integrated with the output guide. Inan embodiment, the yarn brake is a hydraulically controlled brake.

In an embodiment, the tension meter comprises further or alternativemeasuring means, such as a hydraulic or pneumatic plunger instead of ahelical spring, and/or contactless measuring means. In an embodiment,the spool meter is a mechanical meter comprising a lever which is heldunder spring force on the outer surface of the spool.

1. A device for producing an endless winding cable by winding at leastone yarn around two thimbles that are provided at opposite ends of thecable, comprising: an elongated guide and a carriage movably connectedto one another for a movement of the carriage relative to the elongatedguide in a length direction of the elongated guide; a first thimbleholder and a second thimble holder connected to the elongated guide at adistance from one another, with each thimble holder designed to hold oneof the two thimbles; a yarn feeder is connected to the carriage, saidyarn feeder comprising at least one spool holder for holding a spoolwith the at least one yarn, and an output guide for guiding the at leastone yarn to the cable during winding; wherein the output guide and thefirst thimble holder, as well as the output guide and the second thimbleholder, are movable relative to each other in at least a directionperpendicular to the length direction of the elongated guide for guidingthe at least one yarn half a turn around respectively the first one ofthe two thimbles and the second one of the two thimbles during winding;and wherein the yarn feeder comprises at least one yarn brake forcontrolling a tension of the at least one yarn during winding, furthercomprising a control, wherein the at least one yarn brake iscontrollable by the control, and wherein the control is configured toincrease tension during winding, such that tension of the at least oneyarn is greater while winding a subsequent layer of yarn turns than istension of the at least one yarn in at least one of the previous layersof yarn turns.
 2. The device according to claim 1, wherein the controlcomprises a tension meter for measuring a tension of the at least oneyarn at the output guide and/or a spool meter for measuring an outerdiameter of the at least one spool.
 3. A device for producing an endlesswinding cable by winding at least one yarn around two thimbles that areprovided at opposite ends of the cable, comprising; an elongated guide;a carriage movably connected to the elongated guide for a movement ofthe carriage relative to the elongated guide in a length direction ofthe elongated guide; a first thimble holder and a second thimble holderconnected to the elongated guide at a distance from one another, eachdesigned to hold one of the two thimbles, a yarn feeder connected to thecarriage, said yarn feeder comprising at least one spool holder forholding a spool with the at least one yarn, and an output guide forguiding the at least one yarn to the cable during winding, wherein theoutput guide and the first thimble holder, as well as the output guideand the second thimble holder, are movable relative to each other in atleast a direction perpendicular to the length direction of the elongatedguide for guiding the at least one yarn half a turn around respectivelythe first one of the two thimbles and the second one of the two thimblesduring winding, wherein the yarn feeder comprises at least one yarnbrake for controlling a tension of the at least one yarn during winding,wherein the first thimble holder comprises a main frame and a sub-frame,wherein the main frame is connected to the elongated guide, thesub-frame is configured to hold one of the two thimbles, and the mainframe and sub-frame are movably connected to one another for adjustingthe distance between the two thimbles, and wherein the first thimbleholder comprises an actuator for moving the main frame and the sub-framewith respect to one another, and a control which is operativelyconnected to the actuator, wherein the control is configured to decreasethe distance between the first thimble and the second thimble afterwinding a previous layer of yarns and the relevant half turn around thefirst or the second thimble, such that a yarn tension in a subsequentlayer of turns of the at least one yarn is higher than warn tension in aprevious layer of turns of the at least one yarn.
 4. A device accordingto claim 1, wherein the at least one yarn brake is a brake selected fromthe group consisting of: a friction brake, an electro-mechanical brake,and an eddy current brake.
 5. A device according to claim 1, wherein atleast one of the first thimble holder and the second thimble holder isdetachably connected to the elongated guide, and is connectable to theelongated guide at a plurality of different positions along theelongated guide for adjusting the distance between the two thimbles. 6.A method for producing an endless winding cable, comprising the stepsof: positioning a first thimble and a second thimble at a predetermineddistance from one another, which distance corresponds to a requiredcable length, providing at least one yarn, winding the at least one yarnfrom the first thimble to the second thimble, a half turn around thesecond thimble, back to the first thimble, and a half turn around thefirst thimble, repeating the previous step until a predetermined numberof layers of yarn turns is provided in both the first thimble and thesecond thimble, corresponding to a required cable thickness, wherein atension of the at least one yarn is controlled during winding so thattension of the at least one yarn is greater while winding a subsequentlayer of yarn turns than is tension of the at least one yarn in at leastone of the previous layers of yarn turns.
 7. A method for producing anendless winding cable, comprising the steps of: positioning a firstthimble and a second thimble at a predetermined distance from oneanother, which distance corresponds to a required cable length,providing at least one yarn, winding the at least one yarn from thefirst thimble to the second thimble, a half turn around the secondthimble, back to the first thimble, and a half turn around the firstthimble, repeating the previous step until a predetermined number oflayers of yarn turns is provided in both the first thimble and thesecond thimble, corresponding to a required cable thickness, andcontrolling a tension of the at least one yarn during winding so thatthe predetermined distance between the first thimble and the secondthimble is decreased after winding a previous layer of yarns and therelevant half turn around the first or the second thimble, such that ayarn tension in a subsequent layer of turns of the at least one yarn ishigher than yarn tension in a previous layer of turns of the at leastone yarn.
 8. The method according to claim 6, wherein while winding eachsubsequent layer of yarn turns the tension of the at least one yarn isat least equal to or greater, than the tension of the at least one yarnin each previous layer of yarn turns.
 9. The method according to claim6, wherein the tension of the at least one yarn is greater while windinga final layer of yarn turns than the tension of the at least one yarnwhile winding a first layer of yarn turns.
 10. The method according toclaim 6, wherein the tension of the at least one yarn is controlledduring winding by controlling a brake force that is exerted on the atleast one yarn during winding.
 11. The method according to claim 6,wherein the winding of the at least one yarn from the first thimble tothe second thimble, a half turn around the second thimble, back to thefirst thimble, and a half turn around the first thimble, is repeateduntil one layer of a predetermined plurality of yarn turns is providedin both the first thimble and the second thimble, and the tension of theat least one yarn is kept constant while winding the one layer of yarnturns.
 12. A cable, comprising: a first thimble and a second thimbleprovided at opposite ends of the cable; at least one yarn extending fromthe first thimble to the second thimble, turning around the secondthimble, extending from the second thimble to the first thimble, andturning around the first thimble, such that the at least one yarn formsa turn around the first thimble and the second thimble, and each thimbleholds a stack of a plurality of layers of turns of the at least oneyarn, wherein a previous layer of turns of the at least one yarn and asubsequent layer of turns of the at least one yarn are defined withrespect to a center of the respective thimble, and the subsequent layerof turns of the at least one yarn is further away from the center of therespective thimble than the previous layer of turns of the at least oneyarn, and the previous layer of turns of the at least one yarn has afirst yarn tension and the subsequent layer of turns of the at least oneyarn has a second yarn tension, wherein the second yarn tension ishigher than the first yarn tension.
 13. The cable according to claim 12,wherein the stack of a plurality of layers of turns of the at least oneyarn has at least three layers of turns of the at least one yarn, andthe yarn tension in every subsequent layer is at least equal to orhigher than the yarn tension in each of the previous layers.
 14. Thecable according to claim 12, wherein the at least one yarn comprisesfibers selected from the group consisting of: carbon fibers, basaltfibers, or plastic fibers, polyamide fibers, polyester fibers,polypropylene fibers, polyethylene fibers, aramid fibers, HMPE fibers,LCAP fibers, and PBO fibers.
 15. The cable according to claim 12,further comprising a cable cover which extends around the cable from thefirst thimble to the second thimble, and bundles all turns of the atleast one yarn extending between the first and the second thimble in onecompact bundle in a middle section of the cable.
 16. The methodaccording to claim 7, wherein while winding each subsequent layer ofyarn turns the tension of the at least one yarn is at least equal orgreater than the tension of the at least one yarn in each previous layerof yarn turns.
 17. The method according to claim 7, wherein the tensionof the at least one yarn is greater while winding a final layer of yarnturns than the tension of the at least one yarn while winding a firstlayer of yarn turns.
 18. A device according to claim 3, wherein the atleast one yarn brake is a brake selected from the group consisting of: afriction brake, an electro-mechanical brake, and an eddy current brake.19. A device according to claim 3, wherein at least one of the firstthimble holder and the second thimble holder is detachably connected tothe elongated guide and is connectable to the elongated guide at aplurality of different positions along the elongated guide for adjustingthe distance between the two thimbles.